Tikka 223 COAL <2.18 for 75gr BTHP

[Runwilderness]

I have a new Tikka 223 take-off barrel, purchased from UM, never fired/currently not on a action.

Prepping for my trainer build, I purchased 1k factory 2nd 75gr BTHPs from Midway, likely Hornady with cannelure.

I just measured the max COAL to the lands using the hornady guage. I don’t have a 22 cal BTO guage yet, but measuring COAL for 5 bullets is giving me 2.1735 - 2.1810, with the cannelure seemingly 1mm below the top of the neck at this length.

This is way under the 2.26 COAL length I see as the standard Hodgdon and VV load data. I understand that Tikkas are supposed to have short throats…but what gives? The numbers I’m measuring seem to suggest it would be unsafe to fire factory ammo.

I’m hoping user error but I’ve tried several times and get the same results.

Thoughts?

 

[Justin Crossley]

I think you are measuring incorrectly.

I load 75 ELD-M to 2.450" in two factory Tikkas.

 

[Runwilderness]

I think you are measuring incorrectly.

I load 75 ELD-M to 2.450" in two factory Tikkas.

Different bullet without a tip, so I don’t expect to be that long, but I’m also not expecting to be shorter than book loads.

I just gave it another go, making sure to jam the bullet hard enough into the lands to leave it stuck, and cranking the piss out of the screw on the depth rod to keep it from slipping…got a bit longer but something still seems amiss:

 

[SloppyJ]

75gr BTHP is my practice round and I use them for the same purpose in my son's tikka. My rifle is irrelevant due to the extra freebore but in my son's tikka is a stock chamber. I picked up 2k of those bullets and got them dialed in today.

My cbto measurement for touching lands is 1.890". I load them 20 off or at 1.870 for best results in his gun. These are my numbers with my comparator but they are certainly much shorter than other heavy for caliber bullets. I don't have coal measurements for these as I always use cbto.

COAL on 77tmks for his gun is 2.275 at 70 off or a cbto of 1.840. Compared to my measurements your chamber is short. The 77tmks arent that much longer than the 75bthp.

Another thing to compare is the difference from the modified case to your brass. Not OAL but use the headspace gauges.

These measurements are for my rifles with MY comparator. Don't try to copy.

 

[Runwilderness]

@SloppyJ, thanks. This is helpful.

I’ll likely pickup some additional bullets to confirm I don’t just have an issue with the factory 2nds + I may buy a 2nd modified case in case that is somehow bad, as well as pickup gauges for my BTO comp gauge to measure against the different bullets. Since this is a takeoff barrel and I haven’t screwed it on and shot it yet, I can’t compare my brass to the modified case.

I had the barrel cut/threaded before measuring. I don’t see anything in it but I will clean it well and try again, too to be safe.